During Easter dinner I had some delicious ham, potato salad and asparagus. Later that afternoon, I noticed the tell-tale odor in my pee that I always smell after eating asparagus. Don't hide it, many of you know of what I speak. That sort of fruity, rich smell that comes 15 minutes -12 hours after eating asparagus, cabbage, or drinking some varieties of wine or champagne.
This is caused by your body breaking down a molecule found only in certain foods and drinks into a small group of highly aromatic molecules that your kidneys send directly (and very quickly) to your liver.
Here's the kicker: only 22% of people report that smell. Scientists (including myself) jumped to the conclusion that the metabolic pathway for turning asparagus into funny smells was genetic, and only 1 in 5 of us were able to create the smelly compounds. But a smart-thinking scientist tried a test: he took pee containing the smelly compounds and held it under people's noses. Turns out everyone makes the compounds, but only 1 in 5 of us can smell them! The genetic difference is in your nose, not in your intestines.
So the next time you eat asparagus and smell that funky smell, count yourself a part of the minority who still have prehistoric scent glands in their noses. Or if you don't smell anything strange in particular, consider yourself lucky; you're a higher organism than I. You've proudly evolved a less sensitive nose!